The energy required to remove the “outermost” electron from a boron atom is 8.26 eV. As an approximation, you can model the quantum state of this electron as that of a single electron in a hydrogen atom, but with an “effective” charge on the nucleus that is different from the charge of a single proton (+e) as found for a real hydrogen atom. 

(a) Use the Bohr model to estimate the effective charge seen by this electron. 

(b) Estimate the average orbital radius for this electron.